Water-dispersible thermosettable cationic resins and paper sized therewith

ABSTRACT

Disclosed are novel water-insoluble, water-dispersible thermosettable cationic resins derived by reaction of a water-soluble aminopolyamide, a hydrophobizing compound such as a ketone dimer and an epihalohydrin such as epichlorohydrin. The thermosettable cationic resins are water-dispersible, and aqueous dispersions thereof are stable for prolonged periods of time at relatively high solids concentration. The thermosettable cationic resins have particular utility in the sizing of paper.

This is a division of application Ser. No. 393,690, filed Aug. 31, 1973now U.S. Pat. No. 3,922,243.

This invention relates to novel water-insoluble, water-dispersiblecationic thermosettable resins capable of imparting a high degree ofsizing to paper and related cellulosic fibers.

Particularly, this invention relates to novel water-insoluble,water-dispersible cationic thermosettable resins derived by reacting awater-soluble aminopolyamide, a hydrophobizing compound such as a ketenedimer, and an epihalohydrin such as epichlorohydrin.

The water-soluble aminopolyamide is derived by reacting a dibasiccarboxylic acid and a polyalkylenepolyamine.

The water-insoluble cationic thermosettable resins of this invention aredispersible in water at concentrations of the order of, by weight, about8% to about 22%. The aqueous dispersions are essentially stable forprolonged periods of time up to about twelve months and longer.

The water-soluble, water-dispersible cationic thermosettable resins ofthis invention will provide highly satisfactory sizing of paper underneutral conditions, under alkaline conditions, and under acidconditions. Thus, many types of paper can be sized by the use of thenovel cationic thermosettable resins of this invention.

In the preparation of the aminopolyamides for use in the preparation ofthe resins of this invention, a dicarboxylic acid is reacted with apolyalkylenepolyamine, preferably in aqueous solution, under conditionssuch as to produce a water-soluble long chain aminopolyamide containingthe recurring groups ##STR1## wherein R is the divalent hydrocarbonradical of the dicarboxylic acid, n is an integer 2 through 6(preferably 2 or 3), and x will be an integer 2 through 4. As will beapparent, the long chain aminopolyamide will have a plurality ofsecondary amine groups ##STR2##

The dicarboxylic acids that can be used have the structural formulaHOOCRCOOH where R is a divalent hydrocarbon radical. R can be a divalentaliphatic hydrocarbon radical (saturated or unsaturated), or a divalentalicyclic hydrocarbon radical, or a divalent aromatic hydrocarbonradical.

Specific examples of dicarboxylic acids that can be employed includemalonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, fumaric acid, maleic acid, phthalic acid, terephthalicacid, and diglycolic acid. Mixtures of two or more acids can be employedif desired. The available anhydrides of any of the above acids can beemployed as well as esters thereof. The preferred acids are thesaturated aliphatic dicarboxylic acids containing 3 through 8 carbonatoms, that is, R in the above formula contains 1 through 6 carbonatoms.

The polyalkylenepolyamine employed in the preparation of theaminopolyamide has the structural formula ##STR3## wherein n and x areas above defined.

A variety of polyalkylenepolyamines including polyethylenepolyamines,polypropylenepolyamines, polybutylenepolyamines and the like can beemployed herein of which the polyethylenepolyamines are the preferredclass. More specifically, the polyalkylenepolyamines are polyaminescontaining two primary amine groups and at least one secondary aminegroup in which the nitrogen atoms are linked together by groups of theformula --C_(n) H_(2n) -- where n is as above defined.

This invention contemplates not only the use of such polyamines asdiethylenetriamine, triethylenetetramine, tetraethylenepentamine,dipropylenetriamine, and the like, which can be obtained in reasonablypure form, but also mixtures and various crude polyamine materials. Forexample, the mixture of polyethylenepolyamines obtained by the reactionof ammonia and ethylene dichloride, refined only to the extent ofremoval of chlorides, water, excess ammonia, and ethylenediamine, issatisfactory. Most preferred are the polyethylenepolyamines containingfrom two to four ethylene groups, two primary amine groups, and from oneto three secondary amine groups.

The term "polyalkylenepolyamine" employed herein refers to and includesany of the polyalkylenepolyamines referred to above or to a mixture ofsuch polyalkylenepolyamines.

Temperatures employed for carrying out reaction between the dicarboxylicacid and the polyalkylenepolyamine can vary from about 110° C. to about250° C. or higher at atmospheric pressure. Temperatures between about160° C. and 210° C. are preferred. Where reduced pressures are employed,lower temperatures can be utilized as is well known in the art. Reactiontime will usually vary from about 1/2 to 2 hours, although shorter orlonger reaction times can be utilized depending on reaction conditions.Reaction time varies inversely with temperature.

In carrying out the reaction, it is preferred to use an amount ofdicarboxylic acid sufficient to react substantially completely with theprimary amine groups of the polyalkylenepolyamine but insufficient toreact with the secondary amine groups to any substantial extent. Thiswill usually require a mole ratio of polyalkylenepolyamine todicarboxylic acid from about 0.9:1 to about 1.2:1 and preferably from0.92:1 to 1.14:1. However, mole ratios of from about 0.8:1 to about1.4:1 can be used. In preparing the novel resins of this invention, theaminopolyamide is first reacted with a compound (to be detailed morefully hereinafter and to be referred to hereafter as "hydrophobizingcompound") that will produce a water-insoluble reaction product which issometimes referred to hereinafter as a water-insoluble modifiedaminopolyamide or as a modified aminopolyamide. The hydrophobizingcompound is a compound that will react with the secondary amine groupsof the aminopolyamide to form therewith a covalent bond. The amount ofhydrophobizing compound employed will be that sufficient to provide,after reaction, a water-insoluble modified aminopolyamide butinsufficient to react with more than about 50% of the secondary aminegroups of the aminopolyamide. Thus there will be available in themodified aminopolyamide at least about 50% of the original secondaryamine groups of the aminopolyamide reactant for reaction withepihalohydrin. The preferred amount of hydrophobizing compound employedto produce the water-insoluble reaction product or water-insolublemodified aminopolyamide will be that sufficient to react with from about10% to about 25% of the secondary amine groups of the aminopolyamide.Examples of hydrophobizing compounds are acyl halides, acid anhydrides,isocyanates, and ketene dimers. These compounds will contain a total offrom about 12 to about 40 carbon atoms and preferably from about 16 toabout 36.

Acyl halides that can be used have the formula R'COX where x is a halidesuch as chlorine, bromine, iodine, and fluorine. R' is a hydrocarbonradical (saturated or unsaturated) such as alkyl, alkenyl, aryl, andcycloalkyl. The hydrocarbon radical can be a straight or branched chainalkyl radical, an aromatic substituted alkyl radical, an aromaticradical, or an alkyl substituted aromatic radical so long as thehydrocarbon radical contains a total of from about 11 to about 39 carbonatoms and preferably from about 15 to 35 carbon atoms. Specific examplesof acid halides include rosin acid chloride, myristoyl chloride,palmitoyl chloride, oleoyl chloride, and stearoyl chloride.

Acid anhydrides that can be employed include acid anhydrides having thestructural formulae ##STR4## where R' is as defined above and cyclicdicarboxylic acid anhydrides having the structural formulae: ##STR5##where R" represents a dimethylene or trimethylene radical and R'" is ahydrocarbon radical containing more than 7 carbon atoms which isselected from the group consisting of alkyl, alkenyl, aralkyl oraralkenyl. Substituted cyclic dicarboxylic acid anhydrides fallingwithin formula (II) are substituted succinic acid and glutaric acidanhydrides.

Specific examples of anhydrides of formula (I) are rosin anhydride,myristoyl anhydride, palmitoyl anhydride, oleoyl anhydride, and stearoylanhydride.

Specific examples of anhydrides of formula (II) are isooctadecenylsuccinic anhydride; n-octadecenyl succinic anhydride; n-hexadecenylsuccinic anhydride; n-dodecyl succinic anhydride; iso-dodecenyl succinicanhydride; n-decenyl succinic anhydride; n-octenyl succinic anhydride;and n-heptyl glutaric anhydride.

Isocyanates that can be used have the formula R'NCO where R is as abovedefined. Specific examples of such isocyanates are rosin isocyanate,octadecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate,hexyldecyl isocyanate, eicosyl isocyanate, and docosyl isocyanate.

The ketene dimers used in this invention are dimers having the formula[R₁ CH=C=O]₂ where R₁ is a hydrocarbon radical, such as alkyl having atleast 8 carbon atoms, cycloalkyl having at least 6 carbon atoms, aryl,aralkyl and alkaryl. In naming ketene dimers, the radical "R₁ " is namedfollowed by "ketene dimer". Thus, phenyl ketene dimer is: ##STR6##benzyl ketene dimer is: ##STR7## and decyl ketene dimer is: [C₁₀ H₂₁-CH=C=O]₂. Examples of ketene dimers include octyl, decyl, dodecyl,tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosyl, phenyl,benzyl beta-naphthyl and cyclohexyl ketene dimers, as well as the ketenedimers prepared from montanic acid, naphthenic acid, Δ⁹,10 -decylenicacid, Δ⁹,10 -dodecylenic acid, palmitoleic acid, oleic acid, ricinoleicacid, petroselinic acid, vaccenic acid, linoleic acid, linolenic acid,eleostearic acid, licanic acid, parinaric acid, tariric acid, gadoleicacid, arachidonic acid, cetoleic acid, erucic acid, and selacholeicacid, as well as ketene dimers prepared from naturally occurringmixtures of fatty acids, such as those mixtures found in coconut oil,babassu oil, palm kernel oil, palm oil, olive oil, peanut oil, rape oil,beef tallow, lard (leaf) and whale blubber. Mixtures of any of theabove-named fatty acids with each other may also be used.

The reaction of the aminopolyamide and the hydrophobizing compound iscarried out under relatively mild conditions so that no untowardreaction occurs. Thus, the reaction conditions are such that the onlyreaction taking place is the reaction of the hydrophobizing compoundwith the secondary amines of the aminopolyamide whereby the secondaryamines are converted into amides, ureas, beta-ketoamides or beta-amidoacids, depending on the hydrophobizing compound reactant. Thus, theaminopolyamide and hydrophobizing compound are reacted under atmosphericor higher pressure, with or without a catalyst, under a nitrogen blanketat a reaction temperature of from about 0° C. to about 100° C. toproduce a reaction product that is water-insoluble. Suitable catalysts,if one is employed, include tertiary amines such as triethylamine. Theamount of catalyst employed will usually be, by weight, from about 0.1%to about 1% of the total weight of the reactants employed.

The water-insoluble reaction product is then reacted in aqueous mediumor in a suitable solvent therefor (at a solids content of from about 10%to about 40%) with epihalohydrin, preferably epichlorohydrin, at atemperature of from about 20° C. to about 100° C. (preferably from about50° C. to about 70° C.) for a period of time from about 1/2 hour to 3hours (time varies inversely with temperature). The amount ofepihalohydrin used in the reaction with the water-insoluble modifiedaminopolyamide resin will be that sufficient to react with the remainderof the secondary nitrogens of the modified aminopolyamide resin. Thus,the modified aminopolyamide will contain secondary amine groups. Hence,the amount of epihalohydrin employed will be at least that amountsufficient to react with substantially all the secondary amine groups ofthe modified aminopolyamide.

When water is employed as the reaction medium in carrying out thereaction of the modified aminopolyamide resin with epichlorohydrin, thereaction product (which is a water-insoluble thermosettable cationicresin) in its aqueous reaction medium can be homogenized to reduce theparticle size of the solids. Subsequently, the pH of the resultingaqueous dispersion is adjusted to a pH of from about 5 to about 7 toprovide for optimum stability of the dispersion. Stable dispersionshaving a solids content of from about 10% to about 22% can be made bythis means.

The epihalohydrin reaction can be carried out in an organic solventsolution of the water-insoluble modified aminopolyamide resin. Suitablesolvents for the modified aminopolyamide resin include methanol,ethanol, isopropanol, propanol, butanol and benzene. Mixtures of two ormore solvents can be used if desired. It is to be understood that thesolvent employed is nonreactive with the reactants and with the reactionproduct under reaction conditions.

Highly stable aqueous dispersions of the novel resinous reactionproducts of this invention that are prepared in solvent solution can beeasily and readily prepared by the following procedure. In thisinstance, the solvent medium employed will be a solvent not only for thereactants but also for the reaction product. The solution of thereaction product (the reaction product dissolved in the organic solventreaction medium) is dispersed in water with vigorous agitation such, forexample, as by homogenization at pressures of from about 1000 to 5000p.s.i. to provide an aqueous emulsion that is essentially stable.Subsequently, the organic solvent component of the resulting aqueousemulsion is removed by distillation, either under atmospheric conditionsor under vacuum, to provide a stable aqueous dispersion of the reactionproduct.

The aqueous dispersions of the water-insoluble cationic thermosettableresins of this invention are used in the manufacture of sized paper bysurface treatment after sheet formation. In addition, they can beincorporated into a pulp slurry at the wet end of the paper machine toprovide sizing. The amount of resin employed in the sizing of paper willusually be from about 0.05% to about 2% by weight based on the dryweight of the pulp fibers.

The resin is applied in its thermosettable state. It is subsequentlycured, as by application of heat, to its thermoset or cross-linkedstate. Thus, paper, sized in accordance with this invention, willcontain the resin in its thermoset state. Curing or cross-linkinginvolves a time-temperature relationship, time varying inversely withtemperature. Thus, for example, the resin can be cured to its thermosetstate by heating paper containing the thermosettable resin at atemperature of from about 200° F. to 250° F. for a period of from about60 seconds to about 10 seconds. In actual practice, the conventionaldrum drying of the treated paper sheet will provide for sufficientcuring of the resin.

The following examples are illustrative of this invention. All parts andpercentages are by weight unless otherwise specified.

EXAMPLE 1

A 3-liter, 4-necked flask equipped with a mechanical stirrer, water trap(Dean-Stark) with reflux condenser, nitrogen sparge and a thermometerwith a Thermo-Watch temperature controller is charged with 62.4 parts(0.61 mole) of diethylenetriamine. Ninety-two and five-tenths parts(0.63 mole) of adipic acid is slowly added through a powder funnel withgood stirring. The temperature increases to 110° C. by the end of theaddition. The reaction mixture is heated to 170° C. for 2 hours as 20parts of water are collected (22.2 theory). After removing the heatingmantel, about 20 parts of ethanol is added slowly through the condenserwhich lowers the temperature below 100° C. Then about 750 parts ethanolis added to provide a solution having a solids content of about 15%.

EXAMPLE 2

About 750 parts of the solution of Example 1 (cooled to 25° C.) isplaced in a reaction vessel and a solution of 73.0 parts (0.15 mole) ofa mixed hexadecyl-, tetradecyl ketene dimer from a mixture of stearicand palmitic acids in about 650 parts benzene is added dropwise. Theamount of ketene dimer employed is sufficient to react with about 25% ofthe secondary amine groups of the aminopolyamide. This solution remainshomogeneous at room temperature. The reaction mixture is heated toreflux and 42 parts (0.45 mole) of epichlorohydrin is added. After 2hours at reflux the alcohol-benzene solution is blended into 2500 partsof distilled water. The blended dispersion is homogenized at 4000 p.s.i.in a Manton-Gaulin laboratory homogenizer. The dispersion has a pH of 9which is lowered to about 6.5 with formic acid for stabilization. Thesolvent is removed on a rotary evaporator maintaining the bathtemperature below 45°. The resulting product is a turbid, fine particlesize aqueous dispersion having a solids content of about 9.8%.

EXAMPLE 3

The aqueous dispersion of Example 2 is applied to a waterleaf papersheet on a size press by passing the sheet through a solution thereof inthe nip. The amount of size material applied is about 0.21% by weightbased on the weight of the paper. The sized paper sheet is subsequentlydrum dried at 220° F. for about 35 seconds. Sizing results set forthherein are determined on the Hercules Sizing Tester. The sizing testdetermines the resistance of the sized sheet of paper to penetration byNo. 2 Test Solution (an aqueous solution of, by weight, 1.0% formic acidand 1.25% Naphthol Green B). The time necessary for ink penetration toreduce light reflectance to 80% of the sheet's initial value is used torepresent the degree of sizing. The degree of sizing for this example is235 seconds.

EXAMPLE 4

Example 1 is repeated with the exception that the amount of ethanoladded to adjust the solids content (15% solids content in Example 1) isthat amount sufficient to provide a solution having a solids content ofabout 33%.

EXAMPLE 5

To 64 parts of the solution of Example 4 (0.1 equivalent) in a reactionvessel (kept under a nitrogen sparge with magnetic stirring at roomtemperature) is added 9.2 parts (0.03 mole) of rosin isocyanate. As thereaction is heated to reflux, the reaction becomes homogeneous and 100parts of ethanol is added. The solution pH is 8.7. Then, 6.7 parts (0.73mole) of epichlorohydrin is added and the reaction heated to reflux forone hour. The resulting product is blended with 325 parts of distilledwater and the pH thereof (which is 8) is adjusted to 6.5 with formicacid. The blend is then homogenized at 4000 p.s.i. The organic solventportion is removed under reduced pressure leaving a 9.6% total solidsaqueous dispersion. This aqueous dispersion is used to size paper inaccordance with the procedure of Example 2. The degree of sizing forthis example is 155 seconds.

EXAMPLE 6

64 parts of the solution of Example 4 is diluted with 50 parts ofethanol and added to a reaction vessel (kept under a nitrogen spargewith magnetic stirring at room temperature). A solution of 7.5 partsrosin acid chloride in 87 parts of benzene is added slowly at 20° C.After the addition, the reaction mass is heated to reflux and then 6.7parts (0.075 mole) of epichlorohydrin is added and heated an additionalhour at a temperature of 70° C. This product, which is homogeneous, isblended into 200 parts of distilled water and homogenized at 3000 p.s.i.and the solvents removed under reduced pressure. The pH is lowered from7.9 to 6.5 with formic acid. The resulting aqueous dispersion (10.7%solids) is an efficient size on waterleaf paper.

It is understood that the above description and working examples areillustrative of this invention and not in limitation thereof.

What we claim and desire to protect by Letters Patent is:
 1. Acomposition consisting essentially of an aqueous dispersion of awater-insoluble, water-dispersible thermosettable cationic resin derivedby reacting (I) an epihalohydrin and (II) a water-insoluble modifiedaminopolyamide derived by reacting (a) a water-soluble long chainaminopolyamide derived by reaction of a polyalkylenepolyamine and adicarboxylic acid, said aminopolyamide having recurring groups ##EQU1##wherein n is an integer 2 through 6, x is an integer 2 through 4, and Ris a divalent hydrocarbon radical, and (b) an organic isocyanate havingthe formula R'NCO where R' is a hydrocarbon radical containing a totalof from about 11 to about 39 carbon atoms, the amount of organicisocyanate employed being that sufficient to provide a modifiedaminopolyamide that is water-insoluble but insufficient to react withmore than about 50% of the secondary amine groups of the aminopolyamide,the amount of epihalohydrin employed being at least that amountsufficient to react with substantially all the secondary amine groups ofthe modified aminopolyamide.
 2. A composition consisting essentially ofan aqueous dispersion of a water-insoluble, water-dispersiblethermosettable cationic resin derived by reacting (I) epichlorohydrinand (II) a water-insoluble modified aminopolyamide derived by reacting(a) a water-soluble long chain aminopolyamide derived by reaction of apolyalkylenepolyamine and a dicarboxylic acid, said aminopolyamidehaving recurring groups ##STR8## wherein n is an integer 2 through 6, xis an integer 2 through 4, and R is a divalent hydrocarbon radical, and(b) an organic isocyanate having the formula R'NCO where R' is ahydrocarbon radical containing a total of from about 15 to 35 carbonatoms, the amount of organic isocyanate employed being that sufficientto react with from about 10% to about 25% of the secondary amine groupsof the aminopolyamide, the amount of epichlorohydrin employed being atleast that amount sufficient to react with substantially all thesecondary amine groups of the modified aminopolyamide.
 3. Thecomposition of claim 1 wherein the water-soluble long chainaminopolyamide is derived by reaction of diethylenetriamine and adipicacid.
 4. The composition of claim 2 wherein the water-soluble long chainaminopolyamide is derived by reaction of diethylenetriamine and adipicacid.